This invention relates to capacitors, and, more particularly, to a medium to high voltage liquid impregnated, dual dielectric capacitors.
The predominant trends in the electrical and electronic industries are toward smaller sized and lower cost devices and components. Particular effort in this regard has been required by electrical equipment manufacturers who use capacitors because capacitors are frequently large and bulky components in a particular piece of electrical apparatus. Additionally, from the viewpoint of the capacitor manufacturer, these aims freqently conflict. For example, if a capacitor is to be made smaller, yet maintain equivalent voltage and capacitance ratings, these conditions may dictate the use of more costly dielectric materials.
A prior solution to such problems as noted, was to use different solid dielectrics in the same capacitor roll such as paper and plastic films, each forming in conjunction with electrodes, a separate capacitor or parallel capacitor section. In order to take advantage of the self healing properties of metallized layer electrodes, the paper strip was metallized to serve as one electrode and aluminum foil served as the other electrode. Very thin plastic films were used as the other dielectric. In spite of these improvements, demand continues for smaller, more efficient capacitors for motor starting and running applications.
A principal object of this invention, therefore, is to provide an inexpensive, relatively small, high capacitance roll which at the same time is capable of withstanding substantial voltage stress.